ARS | Publication request: Nanostructural characterization of enzymatically modified pectin

Submitted to: Subtropical Technology Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: October 18, 2009
Publication Date: October 22, 2009
Citation: Cameron, R., Luzio, G., Savery, B., Vasu, P., Williams, M. 2009. Nanostructural characterization of enzymatically modified pectin. Subtropical Technology Conference Proceedings. 60:15.

Technical Abstract: Pectin methylesterase (PME) hydrolyzes C6 methyl esters of galacturonic acid (GA) residues in pectin homogalacturonan regions. Both the degree of esterification (DE) and ester spatial distribution affect pectin functionality. We have created a demethylated pectin series with a unique, thermally tolerant PME (TT-PME) and characterized the modified nanostructure. A model pectin (initial DE of 94%) was demethylated to 90, 80, 70, 60 and 50% DE at pH 7.5 and 4.5. A minimum estimate of demethylated block size was obtained by limited digestion with endo-polygalacturonase. With demethylation to 80% and 70% DE at pH 7.5 maximum demethylated block size increased from 6 to 27 respectively and from 27 to 41 when the DE was lowered to 60%. Similar changes also occurred with demethylation at pH 4.5. Average demethylated block size increased more with decreasing DE in the pH 4.5 series. Demethylation patterns obtained with the TT-PME will be compared to those previously reported for the salt independent PME from citrus. These results indicate pectin nanostructure can be manipulated and tailored by enzymatic treatment under controlled conditions.